Conventional disk array data storage systems have multiple disk storage devices that are arranged and coordinated to form a single mass storage system. A Redundant Array of Independent Disks (RAID) system is an organization of data in an array of mass data storage devices, such as hard disk drives, to achieve varying levels of data availability and system performance.
RAID systems typically designate part of the physical storage capacity in the array to store redundant data, either mirror or parity. The redundant information enables regeneration of user data in the event that one or more of the array's member disks, components, or the access paths to the disk(s) fail.
In the event of a disk or component failure, redundant data is retrieved from the operable portion of the system and used to regenerate or rebuild the original data that is lost due to the component or disk failure. This aspect is exacerbated by the increased capacity of the physical drives. Restoring larger physical disks obviously takes longer, which increases the probability of a second failure during the rebuild process.
Accordingly, to minimize the probability of data loss during a rebuild in a hierarchical RAID system, there is a need to manage data recovery and rebuild that accounts for data availability characteristics of the hierarchical RAID levels employed. While a data recovery process is taking place, any additional failure would result in loss of the original user data making an efficient rebuild sequence imperative.
Thus, a need still remains for a disk storage system with rebuild sequence. In view of the overwhelming reliance on database availability, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.